1. Field of the Invention
The present invention relates to a discharge lamp unit capable of supporting a discharge lamp and preventing heat conduction between the discharge lamp and circuit elements forming a lighting unit placed in the inside of a housing case member of the discharge lamp unit, and in particular, the discharge lamp unit having electric wires composed of a base part and branch parts serving as radiation parts in order to efficiently radiate heat energy.
2. Description of the Related Art
There are various types of conventional discharge lamp units, each of which is comprised of, a housing case member, a supporting member capable of supporting a discharge lamp, and a lighting circuit composed of circuit elements to supply electric power to the discharge lamp, such as coils, capacitances, and integrated circuits mounted on a semiconductor substrate. (For example, Japanese patent laid open publication No. JP 2003-022702 discloses such a conventional discharge lamp.)
Because electric wires are made of metal of a high conductivity and connect the circuit elements forming the lighting circuit and the discharge lamp through the supporting member, the electric wires easily conduct heat energy generated in the discharge lamp to the circuit elements placed in the housing case member. This makes it possible to easily heat the circuit elements of the lighting circuit, and thereby to increase the temperature of the circuit elements. As a result, the temperature rise changes and deteriorates the characteristics of the circuit elements.